This invention relates to ion-implanted GaAs and more particularly to encapsulating ion-implanted GaAs during annealing of the composite.
It is well known in the art that ion-implanted GaAs must be annealed to temperatures greater than 800.degree. C. to remove process-induced damage and to induce implanted dopants to go into substitutional or active sites. At this high anneal temperature, arsenic eveporates from the GaAs leaving a non-stoichiometric residue of little technical use. Prior-art methods use SiO.sub.2, Si.sub.3 N.sub.4 or same combination of the two in thin-film form as encapsulants to protect the ion-implanted substrate during the anneal process. These prior-art encapsulants are not lattice-/and thermally matched with GaAs and they are difficult to control during deposition. Thus, alternative encapsulants are desirable.